The light emitting diode (LED) is a kind of semiconductor component. Comparing to the general lighting bulb, the service life of the LED is longer than that of in 50˜100 times; the power consumption of the LED is only ⅓˜⅕ that of the general lighting bulb. Owing to the LED is a tiny lighting source with many advantages such as aforesaid, it will probably dominate the future lighting market and become a new lighting source with benefits in energy saving and environment protecting feature to replace the conventional tungsten and mercury lighting sources in 21 century.
For the illuminating luminance (also known as brightness colloquially), owing to the differences in used material and the epitaxy technique, the LED can be classified into two categories that high luminance LED is the brightness thereof being over 1 candle unit while the low luminance LED is the brightness thereof being less than 1 candle unit. In the initial cradle stages, the popular epitaxy techniques employed are the Hydride Vapor Phase Epitaxy (HVPE), Molecular Beam Epitaxy (MBE), Metal-Organic Vapor Phase Epitaxy (MOVPE) and the like.
For material used in the LED, the physical and chemical properties will considerably change when the dimension of the LED is reduced down to the nano scale. The nano-technology (NT) will become one of the most important technologies as the application of the nano-technology (NT) onto the LED can greatly improve the performance of the LED.
As shown in FIGS. 1 through 3, the nano-structure is produced from conventional nano-lithography. The fabricating steps are as below: (A): Firstly, layout an expected nano pattern Q on a photomask M, then put said photomask M on the top surface of a substrate 1, which is spread with a photo-resist 2 (as shown in the FIG. 1); (B): Secondly, pass a light beam e through said nano pattern Q on said photomask M so as to have same pattern as said nano pattern Q on said photo-resist 2, which spreads on said substrate 1, by exposure and development to define a nano-aperture 3 structure (as shown in the FIG. 2); (C): Thirdly, by means of a deposit source device 30, directly deposit a deposit material B of gas molecule or atom state on the surroundings and bottom of said nano-aperture 3 (as shown in the FIGS. 3a and 3b); and (D): Finally, selectively remove said photo-resist 2 by a solution; thereby a nano quantum dot 4 of nano structure is formed on the surface of said substrate 1 (as shown in the FIG. 3c).
The conventional process aforesaid is confined to the precision limit of the existing photolithography such that the current best precise nano-scale can only reach 60˜65 nm; Hence, the nano-scale of said nano-aperture 3 from photomask M of pattern transferring photolithography is over 60 nm; Thereby, the nano-scale of said nano quantum dot 4 fabricated from these equipment is also over 60 nm relatively; Thus, the physical size limit of said conventional nano-devices of nano-structure are still in the range of over 60 nm; Therefore, how to breakthrough this bottleneck such that making the nano-scale of nano-aperture 3 be smaller becomes the impending crucial technical tough question of all experts in various fields; The solution being subject to the industrial practical feasibility in mass production and cost-effective economical principle so that the choice of means in technical breakthrough becomes more difficult; The scientists who understand the nano-science and the experts who familiarize with nano-technology are all aware of the benefits of working out the nano structure being smaller than 50 nm or even 12 nm, but none of better solution or effective technical breakthrough is proposed, announced or applied, not to mention the fabricating product of LED with the active layer in nano quantum dot grade accordingly.